What is the optimal length for an email address in a database?

Question

Here is an extracted portion of my query, reflecting the EMAIL_ADDRESS column data type and property:

EMAIL_ADDRESS CHARACTER VARYING(20) NOT NU         


        

Answer 1

Variable character types in databases don't occupy unneeded space. Thus, there is no reason to constrain such fields as much as possible. Depending on the name of a person, the naming scheme used by their organization and their domain name, an address can easily exceed 20 characters.

There is no limit as to the length of local-part and domain-name in RFC-2822. RFC-2181 limits the domain name to 255 octets/characters though.

Again, since a varchar only uses the space actually used by the string you store, there is no reason to have a small limit for email address length. Just go with 512 and stop worrying. Everything else is premature optimization